fix sleep

Author: Tieske

lib/resty/timer.lua

@@ -14,58 +14,59 @@ local anchor_registry = {}
 local gc_registry = setmetatable({},{ __mode = "v" })
 local timer_id = 0
 local now = ngx.now
-local sleep = ngx.sleep
+local ngx_sleep = ngx.sleep
 local exiting = ngx.worker.exiting
-local min = math.min
 
 local KEY_PREFIX    = "[lua-resty-timer]"
 local LOG_PREFIX    = "[resty-timer] "
 local CANCEL_GC     = "GC"
 local CANCEL_SYSTEM = "SYSTEM"
 local CANCEL_USER   = "USER"
 
-local sleepx do
-  local SLEEP_BLOCK_SIZE = 5
-
+local sleep do
   -- create a 10yr timer only called with `premature` set. The callback will
   -- release a global semaphore to wake up sleeping threads
   local sema = assert(require("ngx.semaphore").new())
   assert(timer_at(10*365*24*60*60, function()
     sema:post(math.huge)
+
+    -- TODO: remove the below log line, it's an ugly hack around semaphores
+    -- not being released properly, an Openresty bug.
+    -- See https://github.com/openresty/lua-resty-core/issues/337
+    ngx.timer.at(0, function()
+      ngx.log(ngx.WARN,"please ignore, just generating IO, see https://github.com/openresty/lua-resty-core/issues/337")
+    end)
   end))
 
   --- A `sleep` function that exits early on system exit. The same as `ngx.sleep`
   -- except that it will be interrupted when the current worker starts exiting.
   -- @param delay same as `ngx.sleep()`; delay in seconds.
   -- @return results of `ngx.worker.exiting()`
-  -- @usage if sleepx(5) then
+  -- @usage if sleep(5) then
   --   -- sleep was interrupted, exit now
   --   return nil, "exiting"
   -- end
   --
   -- -- do stuff
-  function sleepx(delay)
+  function sleep(delay)
     if type(delay) ~= "number" then
       error("Bad argument #1, expected number, got " .. type(delay), 2)
     end
 
     if delay <= 0 then
-      sleep(delay)
+      ngx_sleep(delay)
       return exiting()
     end
 
-    -- this doesn't work
-    -- see https://github.com/openresty/lua-resty-core/issues/337
-    -- sema:wait(delay)
-    -- return exiting()
-
-    -- fall-back to sleeping in SLEEP_BLOCK_SIZE sec chunks
-    local t = now()
-    local exit_at = t + delay
-    while exit_at > t and not exiting() do
-      sleep(min(SLEEP_BLOCK_SIZE, exit_at - t))
-      t = now()
+    local _, err = sema:wait(delay)
+    if err == "timeout" then
+      return false
     end
+
+    if err then
+      ngx.log(ngx.ERR, "waiting for semaphore failed: ", err)
+    end
+
     return exiting()
   end
 end
@@ -188,7 +189,7 @@ local function handler(premature, id)
     end
 
     -- existing timer recurring, so keep this thread alive and just sleep
-    premature = sleepx(next_interval)
+    premature = sleep(next_interval)
   end  -- while
 end
 
@@ -384,7 +385,7 @@ end
 return setmetatable(
   {
     new = new,
-    sleepx = sleepx,
+    sleep = sleep,
     CANCEL_GC = CANCEL_GC,
     CANCEL_SYSTEM = CANCEL_SYSTEM,
     CANCEL_USER = CANCEL_USER,